The present invention relates to a semiconductor device and a manufacturing method of the same, in particular, to a technology effective when applied to a semiconductor device in which a semiconductor chip is coupled to external coupling terminals through wire bonding or the like.
It is known that when after processing treatment (wafer processing step), a passivation film, a polyimide layer, and the like are formed on a substrate and then, a bonding wire made of Cu (copper) or Au (gold) is electrically coupled to a semiconductor chip, a redistribution layer electrically coupled to elements on the upper surface of the substrate is formed on the semiconductor chip and a bonding wire is coupled onto a pad on the redistribution layer. As the bonding pad for coupling the bonding wire thereto, for example, Au (gold) is used.
Patent Document 1 (Japanese Patent Laid-Open No. 2001-53075) describes that a Cu (copper) deposit layer is subjected to isotropic etching to secure a space for the formation of a covering layer and then, a Ni/Au deposit layer is formed in the space. According to this document, a Ni/Pd deposit layer may be formed instead of the Ni/Au deposit layer on the surface of a redistribution layer made of the Cu (copper) deposit layer. Since the above-mentioned etching makes the pattern width of the redistribution layer narrower than that of the Cu (copper) deposit layer, a deposit layer formed on the redistribution layer covers the upper surface and side surface of the redistribution layer. This document does not include a description on a Ni (nickel) film and a Pd (palladium) film configuring the Ni/Pd deposit layer and the relationship of their thickness. In addition, according to this document, a wire made of Au (gold) is bonded to a bonding pad on the redistribution layer.
Patent Document 2 (Japanese Patent Laid-Open No. 2005-150578) describes the use of a film stack of a Ti (titanium) film and a Pd (palladium) film stacked in the order of mention as a redistribution layer to be used as an underlying film of an Au bump.
Patent Document 3 (Japanese Patent Laid-Open No. 2001-244287) describes the formation of a Cu (copper) film having a thickness of from a few hundred nm to a few thousand nm, followed by formation thereon a cap metal made of, for example, Ni (nickel), Au (gold), Pt (platinum), or Pd (palladium), or an alloy thereof, as films configuring a redistribution layer.